Engineering Properties On Yellow River Alluvial-plain Soil

It is seriously important to study the engineering characteristic of Yellow River alluvial-plain soil, as it is the most basic building material because of the lack of sandstone there, and a specific soil in our country.Through the experiment, the characteristics of the Yellow River alluvial-plain soil were analyzed. The soil presents in layered form on the structure, and is mainly made up of original mineral grit and rarely clay mineral. In the distribution of grain, it is epigranular, and the content of silt is more than 80%. It has high psephicity, low surface strengths, high porosity and intensive capillarity because of the long transport function of the water. It also has higher groundwater level in district and bigger compressibility. So the Yellow River alluvial soil expresses some engineering characteristics, such as, difficultly to be compacted and stabilized with inorganic binder, and large foundation depression.In the test, the compaction performance of the Yellow River alluvial soil was analyzed. The high porosity after compaction is the main reason of its strong capillarity and high frost susceptibility, as well as the larger foundation depression. The content of the grain, which is smaller than 0.005mm, reflects optimum grading limit of rolling grains. Through the jolter experiment, the vibrating compaction regulation of the soil was studied. The reasonable compaction craft was put forward on trial road.In the experimental investigation, the strength regulation, the strength influencing factors and its action mechanism, design method of ratio of conjugation, maintenance process and compaction craft of the Yellow River alluvial soil stabilized with the inorganic binder were studied. The low content of clay is the main reason that the performance of the soil stabilized with inorganic binder is poor. The reasonable design age was put forward based on the intensity phase of lime-flyash soil. The controlling parameter of Yellow River alluvial soil stabilized with lime-flyash soil and optimum ratio of conjugation limit were given. The key control parameter, the content of grains which is smaller than 0.005 mm, and the important parameter reflecting quality and activity of grain gradation--the coarse-to-fine grain ratio Cf, were taken out.The fluid-solid coupling model of foundation depression was set up through the finite difference calculus. The regulation of the foundation depression was analyzed. The resting period, sedimentation rate and consolidation time of different filled-up subgrades were extracted.The mechanical response of freeway pavement structure in this area was analyzed. The engineering technique measure, which is treating road bed to increase fatigue resistance, was put forward. And pointing out three factors which influence the stress and service life, they are poling condition of pavement structure, the interface and the rigidity difference between layers. The position of maximum tension stress of semi-rigid asphalt pavement structure, critical load zone, influencing depth and the position of plastic yield in the roadbad were presented. The reliability of compute results was verified by the field test.